Boats having a stern compartment provided with at least one closing stern hatch of its own are known for a long time. Such a compartment is used, for instance, to house a small boat or a tender. It is also known that in the stern portion, many prestigious boats have a stern platform determined by a projecting plane suitable for operating as a “small beach” for the boat's passengers.
With reference to said hatch, it can be moved with the purpose of freeing or closing an aperture to access the stern compartment (from the sea or from the stern platform). For this purpose, actuating members are usually provided, usually in the form of telescopic members which constrain the body of the hatch to side walls of the stern compartment.
The requirement is also known of allowing an easy submersion of the tender into the water and an easy recovery thereof into the hull. This is advantageously obtained by making the stern platform movable with respect to the hull and such as to make it possible to submerge it into the water on which the boat floats. This frees the access of the tender into the water and its picking up from the surface, for instance from the sea whenever the tender or dinghy is to be hauled in and put again in the hull. For this purpose, the platform is made movable, for instance, by means of telescopic systems supporting and constraining the platform to the hull which can bring said stern platform above the water surface or submerge it therein. In the first position, external to water, such platform can be used as a “small beach” on the rear side of the boat.
The presence of such stern platform offers comfort to the people on board the boat, a comfort that is directly proportional to the surface of the platform: the wider is it, the more is the “small beach” offered to such people. However, on the contrary, this is at odds with the need for having no rear or stern parts projecting from the hull in order to make its berthing in harbors easier. It follows that such platforms necessarily have reduced dimensions as to their extension from the hull.
US2006/0075952 and US2010/0288179 disclose a movable platform unit for a boat suitable for launching or hauling out a tender or similar water craft. Such unit comprises a base with a movable platform pivoted thereon and comprising a cavity for housing the movable platform. When in its closed position, i.e. when the platform is in said cavity, the platform precisely fits the overall shape of the base. The cavity houses a pair of fixed arms and swing arms are connected to distal ends of said fixed arms and can turn in a vertical plane perpendicular to the plane of the base of the platform unit. To the swing arms, a plurality of turnable steps are connected.
The distal ends of the swing arms are connected by a cross member also turnable about its longitudinal axis relative to the swing arms and a pair of supports is fixed one to each end of the cross member so as to be pivoted on the swing arm. Said supports are provided for mounting the movable platform.
These prior documents describe that the platform can be lowered beneath the surface of the water making it possible to launch or haul back on board a tender or similar craft associated with the boat, while the steps give swimmers easy access to the water.